note that presently this listing combines a relatively deep plume hit with reports of a relatively shallow active vent field, thus this is likely to be split into 2 listings; R/V Poseidon 436 cruise report: off-axis at 71 08.088'N, 13 03.395'W, northernmost Kolbeinsey Ridge: "We interpret the plume anomaly measured at station MA_193 to have been created by hydrothermal activity at the adjacent ridge axis. The ridge axis is at about 2200 m depth", "in the course of surveying and sampling work, the ridge axis was also thoroughly prospected for hydrothermal activity both by the AUV and by the use of MAPR attached to the sampling cable.", "We did not detect any undisputable hydrothermal signal at any other stations during the cruise"; R/V G.O. Sars cruise in June/July 2013, http://www.uib.no/en/geobio/57318/research-overview, accessed 5 June 2015: "water column detection was also used at the Northern Kolbeinsey Ridge to successfully locate the first hydrothermal systems ever found at this site."; Centre for Geobiology Annual Report 2014, accessed 10 June 2015: "At the northernmost segment of the Kolbeinsey Ridge we visited another vent system discovered in 2013. The Seven Sisters Vent Field, located across a flat-topped chain of volcanic edifices at only ~150 m water depth, is the first vent field found in the northern sector of the Kolbeinsey Ridge. Here, relatively hot (~200 C) and clear fluids vent from barite-rich vent structures with native sulfur"; used latitude to estimate spreading rate from Bird (2003) model;

Year and How Discovered (if active, visual confirmation is listed first):